1. Field of the Invention
Aspects of the present invention relate to communication systems. More particularly, aspects of the present invention relate to controlling access on wireless communication systems.
2. Description of Related Art
Wireless transmission systems are used for both data and voice transmissions. While data transmissions are generally immune to minor delays because of network traffic, voice transmissions are not so immune. Quality of service guarantees (QoS) are often provided to voice users to minimize delays. These guarantees often lead to unnecessary regulation of an access point and minimize the number of users who can use the access point at any given time.
The IEEE 802.11 standard is the most commonly deployed Wireless Local Area Network (WLAN). While 802.11 offers high-speed wireless data access it is not well suited for isochronous services that require bounded delays such as voice, video, and other interactive applications. This problem stems from limitations in the mandatory medium access (MAC) protocol used in 802.11—called the Distributed Coordination Function (DCF). The DCF cannot perform scheduling and has no mechanism to ensure that delays are bounded. Moreover, the DCF is based on a random contention process that is unable to selectively favor individual terminals, i.e. the DCF mode cannot preferentially treat—by granting increased access rights to the medium—one terminal over another. As a consequence, 802.11 DCF terminals cannot be guaranteed contention-free access to the medium and cannot offer bounded delays to isochronous services.
An improvement is needed for handling voice transmissions in wireless networks.